小麦ARF基因家族生物信息学分析及在干旱胁迫下的表达特性研究

Bioinformatics Identification of Auxin Response Factor Genes and Expression Profiles under Drought Stress in Wheat

植物生长素响应因子ARF(auxin response factor)参与调节了植物的向性运动、顶端优势、微观的分化、侧根和茎的形态发生等众多生理反应,在植物生长发育的整个过程都起到重要调控作用。本研究通过对小麦最新基因组数据进行分析,获得了61个ARF家族基因,命名为TaARFs,根据染色体编号排列为TaARF1~TaARF61,对61个TaARFs基因进行系统生物信息学分析后发现ARF家族基因结构较为复杂,外显子数量从1个到15个变化不等,除了4号染色体和5A和5B染色体之外,其余的染色体均有ARF家族基因分布。ARF家族基因大多包含B3 DNA结构域、ARF结构域(Auxin-resp)和Aux/IAA结构域;同源进化分析表明,小麦ARF家族基因的旁系同源基因数量明显多于大麦和二穗短柄草。通过拟南芥数据库比对获得14个高同源的根系发育相关的小麦ARF家族基因,利用二系杂交小麦京麦6号及父母本根系为试材进行干旱胁迫处理及实时荧光定量PCR(qPCR)筛选。结果表明,7个小麦ARF基因不同程度受到干旱胁迫诱导,其在旱胁迫下的表达量显著高于正常条件下的表达量,可能参与干旱胁迫应答;此外本研究还发现,ARF基因在F1杂交种中表达量显著高于双亲,表现出超亲表达模式,可能参与了根系抗旱杂种优势基因表达调控网络。

Auxin response factors （ARFs）, which activate or repress the auxin response genes by binding to auxin response elements（AuxREs） on promoters, are essential to auxins signal transduction and act as critical roles in modulating various biological processes. In this study, TaARF genes were comprehensively identified from current wheat genome by using bioinformatics methods and gene structure, chromosome location prediction, conserved domain of proteins, homologous evolution and homologous protein were analyzed. Results showed that 61 TaARF genes were identified, which were located on the chromosomes except chromosome 4A,4B,4D, 5A and 5B. The nomenclature was based on the positions of the wheat chromosomes. TaARF genes had complex structure. The num- ber of exons varied from 1 to 15, most of TaARF genes contained conserved B3 domain, Auxin-resp domain and Aux/IAA domain. Analysis for homologous evolution showed that the number of paralogs of TaARF genes were more than HvARF genes and BdARF genes. Fourteen TaARF genes which were related to root development were gained by using sequence alignment to the Arabidopsis database. A wheat line JM6 was subjected to drought stress treatment followed qPCR analysis of the 14 genes. Seven genes showed more than 5 times over control in expression level. Compared with its parents, F1 hybrids had a higher expression level. Based on these results, we speculated that TaARF genes played an important role in response to drought stress. These might be involved in the heterosis and the gene expression regulation network of root drought tolerance.